PRINCIPLE OF NATURAL SELECTION. 21$ 



trine to impress itself upon scientific men. 

 The difficulty did not lie in the circumstance 

 that the facts of botany and zoology were 

 opposed to it; for it first took its rise out of 

 them. The affinities of species and of the 

 higher groups, and the facts of embryology, 

 distribution, and palaeontology by themselves 

 were sufficient to force the conviction that 

 species are derived, and the doctrine would 

 doubtless have won its way at once had it not 

 had to make head against the imported belief 

 in creation. Had the doctrines of descent and 

 creation been for the first time presented to the 

 scientific mind as alternative beliefs, there can 

 be no doubt that the former would have been 

 chosen as the true explanation of the facts, 

 even though no force capable of producing the 

 effects had been assigned. The cause would 

 still remain to be investigated, while the facts 

 would be brought together under a single point 

 of view. With the adoption of creation as an 

 explanation, an efficient cause is provided, but 

 the facts remain worthless either to prove or 

 to disprove the doctrine. It is not enough that 

 a cause should be capable of producing given 

 effects, but it should produce the given effects 

 and be incapable of producing any other set 

 of effects. In short, by the former view the 



